JP7320447B2 - Casting mold and casting manufacturing method - Google Patents

Description

The present invention relates to technology for manufacturing castings.

Patent Literature 1 discloses that a mold member forming a mold is formed with a gas release groove for discharging gas in a mold cavity to the outside of the mold.

JP-A-2008-6469

The degassing grooves as described above are provided in order to suppress poor molten metal circulation in the mold during casting.

In some casting operations, molten metal may enter the gas groove. If the molten metal that has entered the gas groove solidifies and is released from the mold together with the casting, an unexpected protrusion (sometimes called burr) may occur on the casting. In addition, if the casting is removed from the mold while the molten metal that has entered the groove solidifies and remains in the groove, part of the casting will remain on the mold side along with the solidified material in the groove, resulting in unexpected damage to the casting. dents (sometimes called reverse burrs) may be formed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to suppress projections or depressions that occur unexpectedly in a casting in a casting mold.

In order to solve the above problems, a casting mold has a first mold component having a first mold surface and a first mating surface, a second mold surface and a second mating surface, The second mold surface is disposed so as to be continuous with the first mold surface, and the second mold component is combined with the first mold component in a state in which the second mating surface is opposed to the first mating surface. and a second mold part that extends outward from between the first mold surface and the second mold surface while intersecting at least one of the first mating surface and the second mating surface. A plurality of gas venting grooves are formed in this direction.

Further, in order to solve the above problems, a casting manufacturing method has a first mold component having a first mold surface and a first mating surface, a second mold surface and a second mating surface, The second mold surface is disposed so as to be continuous with the first mold surface, and the first mold component is placed in a state in which the second mating surface is opposed to the first mating surface. and a second mold part to be combined, wherein the mold part extends outward from between the first mold surface and the second mold surface while intersecting at least one of the first mating surface and the second mating surface. A method for producing a casting using a casting mold, wherein a plurality of gas vent grooves directed in the direction of (b) the molten metal in the mold space solidifies; , provided.

According to this casting mold, at least one of the first mating surface and the second mating surface is provided with a plurality of outwardly facing surfaces between the first mold surface and the second mold surface while intersecting each other. Since the gas release grooves are formed, a large number of gas release paths are formed. At the position where the gas venting grooves intersect, the gas venting paths merge and branch. Therefore, even if the inlets of some of the plurality of gas venting grooves are clogged with molten metal, the downstream path of the intersecting position can be made to function as the gas venting path. Thereby, the degassing effect is maintained over a long period of time. In addition, the opening of the inlet can be made smaller by allowing a portion of the inlet to be blocked by the molten metal. This makes it difficult for molten metal to enter. Therefore, projections or depressions that occur unexpectedly are suppressed.

Moreover, according to this casting manufacturing method, castings with few shape defects can be manufactured.

1 is a schematic perspective view showing a casting mold according to an embodiment and a casting in the casting mold; FIG. FIG. 2 is a partial cross-sectional view of the casting mold and casting taken along line II-II of FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; 4 is a partially enlarged view of FIG. 3; FIG. FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; It is explanatory drawing which shows the relationship between molten metal and a gas vent groove.

A casting mold and a casting manufacturing method according to an embodiment will be described below. FIG. 1 is a schematic perspective view showing a casting mold 20 and a casting 10 within the casting mold 20. FIG. FIG. 2 is a partial cross-sectional view of casting mold 20 and casting 10 taken along line II-II of FIG. FIG. 3 is a cross-sectional view taken along line III--III of FIG. For convenience of explanation, the vertical direction based on the direction of gravity may be referred to in each drawing.

The casting 10 is a molded product formed by casting. The casting method is a molding method in which a metal such as an aluminum alloy is melted to form a molten metal, the molten metal is poured into the casting mold 20, and the molten metal is solidified into a predetermined shape in the casting mold 20. Casting 10 is manufactured, for example, by low pressure casting or gravity casting.

In this embodiment, casting 10 is a cylinder head in an internal combustion engine. The cylinder head may be provided with fins to increase the surface area and improve heat dissipation. When such a cylinder head is mounted on a motorcycle, it becomes a portion exposed to the outside.

Casting 10 has a fin-shaped portion 12 forming a fin. The fin-shaped portion 12 is a flat-shaped portion, in other words, a thin plate-shaped portion. In this embodiment, casting 10 includes body portion 11 and a plurality of fin-shaped portions 12 . The body portion 11 is a portion that continues to the plurality of fin-shaped portions 12 . Here, the main body part 11 is formed in a tubular shape having a space open on one side. In FIG. 1, the opening of the body portion 11 faces upward. The vertical direction of the casting mold 20 during casting does not have to match the vertical direction of the manufactured casting 10 in use. The vertical direction in each drawing is based on the state at the time of casting. A plurality of fin-shaped portions 12 are formed around the outer circumference of the body portion 11 . The fin-shaped portion 12 is formed in a shape protruding outward from the outer periphery of the main body portion 11 of the casting 10 in the shape of a flange. The plurality of fin-shaped portions 12 are arranged side by side with a gap in the vertical direction. The fin-shaped portion may partially protrude around the body portion.

The casting mold 20 is a mold for manufacturing the casting 10 . In this embodiment, the casting mold 20 is made of metal or the like, and includes a base mold 28 , a plurality of intermediate molds 30 , 32 , 34 and 36 and an upper mold 40 . A plurality of intermediate molds 30 , 32 , 34 , 36 are molds sandwiched between the base mold 28 and the upper mold 40 . The base mold 28, the first intermediate mold 30, the second intermediate mold 32, the third intermediate mold 34, the fourth intermediate mold 36, and the upper mold 40 are arranged in this order from bottom to top, Stacked. A mold space 22 for forming the casting 10 is formed inside the combination of the base mold 28 , the plurality of intermediate molds 30 , 32 , 34 , 36 and the upper mold 40 .

The base mold 28 is the lowermost portion of the casting mold 20 and forms the surface of the lower portion of the casting 10 . Here, the base mold 28 has a fin-side mold surface 28A that forms the lower surface of the lowermost fin-shaped portion 12, and a body-side mold surface 28B that forms the lower surface of the main body portion 11 of the casting 10. have. A mating surface 29 facing another mold is formed in a portion surrounding the mold surfaces 28A and 28B in the upper portion of the base mold 28 . More specifically, the base mold 28 is formed in a vertically flattened rectangular parallelepiped shape. A fin-side mold surface 28A and a body-side mold surface 28B are formed in the middle portions of the upper surface of the base mold 28 in the left, right, and front and rear directions. The mating surface 29 may be formed along a horizontal plane perpendicular to the direction of gravity. Here, the mating surface 29 is formed flat. The body-side mold surface 28B is formed in a flat plane along the horizontal direction at a position lower than the mating surface 29. As shown in FIG. The fin-side mold surface 28A extends horizontally outward from the outer peripheral edge of the main body-side mold surface 28B, and gradually rises outward along the outer circumference to reach the mating surface 29. formed in Here, the outer peripheral portion 28Aa of the fin-side mold surface 28A is formed in a shape that forms a curved surface that is convex obliquely downward and outward in the longitudinal section.

A first intermediate mold 30 is overlaid on the base mold 28 . The first intermediate mold 30 is formed in a plate shape having a width corresponding to that of the base mold 28 . The first intermediate mold 30 is a portion of the casting 10 that forms an intermediate region partitioned by the plurality of fin-shaped portions 12, and is the extension of the surface along the intermediate portion in the thickness direction of each fin-shaped portion 12. Separated from the mold. Mold surfaces 30A, 30B, and 30C are formed so as to penetrate vertically through the intermediate portion of the first intermediate mold 30 in plan view. The lower mold surface 30A is shaped to define the upper surface of the lowermost fin-shaped portion 12 . In other words, the fin-side mold surface 28A of the base mold 28 and the lower mold surface 30A are continuously arranged to form a flat mold space that forms the lowermost fin-shaped portion 12. be done. At this time, the fin-side mold surface 28A forms the lower surface of the fin-shaped portion 12, and the lower mold surface 30A forms the upper surface of the other fin-shaped portion 12. The intermediate mold surface 30B is formed in a shape that forms the outer peripheral surface between the lowermost fin-shaped portion 12 and the second fin-shaped portion 12 from the bottom of the main body portion 11 . The upper mold surface 30C is shaped to form the upper surface of the second lowest fin-shaped portion 12 from the bottom. A portion of the lower surface of the first intermediate mold 30 surrounding the lower mold surface 30A is formed as a mating surface 31A. The mating surface 31A may be formed along a horizontal plane perpendicular to the direction of gravity. Degassing grooves 31G1 and 31G2 are formed in the mating surface 31A. A formation example of the gas release grooves 31G1 and 31G2 will be described later. A portion of the upper surface of the first intermediate mold 30 surrounding the upper mold surface 30C is formed as a mating surface 31B. The mating surface 31B may be formed along a horizontal plane perpendicular to the direction of gravity. In this embodiment, the mating surface 31B is formed flat.

The intermediate mold surface 30B is formed in an annular shape in a vertically intermediate region with respect to the mating surfaces 31A and 31B. The lower mold surface 30A extends horizontally outward from the lower edge of the intermediate mold surface 30B, and is shaped so as to reach the mating surface 31A gradually downward as it goes outward on its outer circumference. It is formed. Here, the outer peripheral portion of the lower mold surface 30A is formed in a curved shape so as to protrude outward. When the first intermediate mold 30 is overlaid on the base mold 28, the mating surface 31A is arranged to face the mating surface 29. As shown in FIG. Further, the downward portion of the lower mold surface 30A extending in the horizontal direction is arranged to face the upward portion of the fin-side mold surface 28A extending in the horizontal direction. Further, the outer peripheral portion of the lower mold surface 30A is arranged continuously above the outer peripheral portion of the fin-side mold surface 28A. Thereby, a vertically flat mold space is formed in which the lowermost fin-shaped portion 12 can be formed. At this time, the upper mold surface 30C forms one surface side (lower side) of the fin-shaped portion 12, and the lower mold surface 30A forms the other surface side (upper side) of the fin-shaped portion 12. The upper mold surface 30C extends horizontally outward from the upper edge of the intermediate mold surface 30B, and is shaped to reach the mating surface 31B as it extends outward along the outer periphery thereof. be done. Here, the outer peripheral portion of the lower mold surface 30A is formed in a curved shape so as to protrude outward.

The second intermediate mold 32, the third intermediate mold 34, and the fourth intermediate mold 36 have the same configuration as the first intermediate mold 30, and have mold surfaces 30A, 30B, 30C and mating surfaces 31A, 31B, respectively. have Also, gas release grooves 31G1 and 31G2 are formed in the respective mating surfaces 31A. When the intermediate molds 30, 32, 34, and 36 are superimposed, a lower mold surface 30A on the upper mold side and an upper mold surface 30A on the lower mold side are placed between the vertically opposed ones. A mold space in which the fin-shaped portion 12 can be formed is formed by the mold surface 30C. Also, the mating surface 31A and the mating surface 31B are arranged to face each other.

The upper mold 40 is the uppermost part of the casting mold 20 and forms the upper part of the casting 10 . Upper mold 40 may shape the interior surface of casting 10 . Here, the upper mold 40 has a mold face 40A that forms the upper surface of the top fin-shaped portion 12 . The upper mold 40 is formed in a plate shape having a width corresponding to that of the fourth intermediate mold 36 in plan view. A portion of the lower surface of the upper mold 40 surrounding the mold surface 40A is formed as a mating surface 41 . The mating surface 41 may be formed along a horizontal plane perpendicular to the direction of gravity. Here, gas release grooves 31G1 and 31G2 are formed in the mating surface 41. As shown in FIG. An inner mold 140 is arranged in the upper mold 40 . This inner mold has an inner mold surface 40B that forms the surface of the internal structural portion of the main body portion 11 of the casting 10 .

The mold surface 40A extends horizontally outward from the outer circumference of the mold surface 40B, and is shaped to gradually reach the mating surface 41 as it extends outward from the outer circumference. Here, the outer peripheral portion of the mold surface 40A is formed in a curved shape so as to protrude outward.

When the upper mold 40 is overlaid on the fourth intermediate mold 36, the mating surface 41 is arranged to face the mating surface 31B. Also, the mold surface 40A is arranged to face the upper mold surface 30C, thereby forming a mold space in which the uppermost fin-shaped portion 12 can be formed. The inner mold 140 is arranged in a space surrounded by the intermediate mold surface 30B.

A mold space 22 in which the casting 10 can be formed is formed by the mold surfaces 28A, 28B, a plurality of sets of mold surfaces 30A, 30B, 30C, and the mold surfaces 40A, 40B. A supply port 24 capable of supplying the molten metal L to the mold space 22 is provided (see FIG. 2). For example, molten metal melted in a furnace is pushed up by gas pressure and poured into the mold space 22 through the supply port 24 .

Regarding the relationship between the base mold 28 of the present embodiment, the plurality of intermediate molds 30, 32, 34, 36, and the upper mold 40, which are vertically combined, the following may be grasped. good. First, the lower mold is the first mold, and the mold surface and the mating surface formed on the lower first mold and provided on the upper mold side are the first mold surface and the first mating surface. It can be understood as a face. In addition, the upper mold is the second mold, and the mold surface and the mating surface formed on the upper mold and provided on the lower mold side are the second mold surface and the second mating surface. You may

For example, regarding the relationship between the base mold 28 and the lowest first intermediate mold 30, the base mold 28 may be understood as the first mold and the first intermediate mold 30 as the second mold. In this case, the fin-side mold surface 28A and the mating surface 29 formed on the base mold 28 may be grasped as the first mold surface and the first mating surface. Also, the lower mold surface 30A and the mating surface 31A formed on the first intermediate mold 30 may be grasped as the second mold surface and the second mating surface. Also, for example, regarding the relationship with the plurality of intermediate molds 30, 32, 34, 36, for example, the second intermediate mold 32 is the first mold, and the third intermediate mold 34 above it is the second mold. You can grasp. In this case, the upper mold surface 30C and the mating surface 31B formed on the second intermediate mold 32 may be grasped as the first mold surface and the first mating surface. Further, the lower mold surface 30A and the mating surface 31A formed on the third intermediate mold 34 may be grasped as the second mold surface and the second mating surface. Regarding the space between the fourth intermediate mold 36 and the upper mold 40, similarly to the above, the fourth intermediate mold 36 may be regarded as the first mold and the upper mold 40 as the second mold.

Focusing on the space between the second intermediate mold 32 and the third intermediate mold 34, the gas release grooves 31G1 and 31G2 will be described more specifically. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a cross-sectional view taken along line VV of FIG. As shown in FIGS. 2 to 5, gas release grooves 31G1 and 31G2 are formed in the upper mating surface 31A as the second mating surface. Gas release grooves 31G1 and 31G2 extend parallel to the direction in which mating surface 29 extends.

The gas release grooves 31G1 and 31G2 are formed so as to extend further outward from the boundary between the mold surfaces 30A and 30C for forming the fin-shaped portion 12. As shown in FIG.

The gas release grooves 31G1 and 31G2 are formed as passages that communicate the mold space 22 and the space outside the mold. Gas extruded by the molten metal guided to the mold space 22 passes through the gas vent grooves 31G1 and 31G2, so that the filling amount of the molten metal in the mold space 22 can be increased. By setting the pressure in the space outside the mold to be lower than the pressure in the mold space 22, the gas may be easily guided to the gas vent grooves 31G1 and 31G2.

The gas release grooves 31G1 and 31G2 extend perpendicularly to the thickness direction of the fin-shaped portion 12 in relation to the fin-shaped portion 12, and their openings face the tip portions of the fin-shaped portion 12. As shown in FIG. Here, the fin-shaped portion 12 has a tip shape in which the dimension in the thickness direction becomes smaller as it progresses in the projecting direction away from the main body portion 11 . The gas release grooves 31G1 and 31G2 are formed so as to reach the space outside the mold from a position facing the fin-shaped portion 12 of the casting mold 20. As shown in FIG. In the casting mold 20, the degassing grooves 31G1 and 31G2 are formed outside the mold space 22, thereby realizing a structure for degassing.

In this embodiment, the casting mold 20 is a slide mold. In this embodiment, the casting mold 20 is a slide mold that is divided by a division plane B along the direction of gravity and is slidable. For example, after the casting 10 is molded in the casting mold 20, the casting mold 20 is separated at the dividing plane B and slid in the directions away from each other (dividing plane B in FIG. 1, arrow P ), the casting 10 is released from the casting mold 20 .

The gas release grooves 31G1 and 31G2 extend parallel to a virtual plane extending parallel to the sliding direction of the casting mold 20. As shown in FIG. In other words, the gas vent grooves 31G1 and 31G2 extend parallel to a plane extending in a direction perpendicular to the thickness direction of the fin-shaped portion 12. As shown in FIG.

The tip portion of the fin-shaped portion 12 extends along the edge in the direction perpendicular to the thickness direction of the fin-shaped portion 12 . The gas release grooves 31G1 and 31G2 are formed in regions surrounding the edges of the fin-shaped portion 12 from the outside. The inner openings of the gas release grooves 31G1 and 31G2 are formed so as to line up along the edge of the fin-shaped portion 12. As shown in FIG. In the present embodiment, the formation regions of the gas release grooves 31G1 and 31G2 are formed so as to surround the edge of the fin-shaped portion 12. As shown in FIG.

In this embodiment, a plurality of linear gas vent grooves 31G1 are formed in parallel at intervals in the portion where the mating surface 31A is formed. Further, a plurality of linear degassing grooves 31G2 are formed in parallel at intervals in the portion where the mating surface 31A is formed.

The plurality of gas vent grooves 31G1 and 31G2 includes a first group of gas vent grooves 31G1 and a second group of gas vent grooves 31G2. The gas vent grooves 31G1 of the first group extend in a predetermined first extending direction and are arranged in a first parallel direction orthogonal to the first extending direction. The gas vent grooves 31G2 of the second group extend in a second extension direction that is different from the first extension direction, and are arranged in a second parallel direction perpendicular to the second extension direction. The first extending direction and the second extending direction extend in directions inclined with respect to the sliding direction of the casting mold 20 . For example, each extending direction is inclined with respect to the slide direction P by ±45 degrees. Moreover, each extending direction extends in a direction that is inclined with respect to the direction extending from the base end to the tip of the fin-shaped portion 12 . In other words, it extends in a direction that is inclined with respect to the normal to the edge of the fin-shaped portion 12 .

The spacing between the plurality of gas release grooves 31G1 belonging to the first group may be the same as or different from the spacing between the plurality of gas release grooves 31G2 belonging to the second group. In the mating surface 31A, a plurality of linear gas vent grooves 31G1 and a plurality of gas vent grooves 31G2 intersect each other. The crossing angle at this time is arbitrary. The crossing angle is, for example, 90°. As a result, gas vent grooves 31G1 and 31G2 are formed in a mesh shape, a so-called lattice shape, in the portion where the mating surface 31A is formed.

An intersection area where the gas vent grooves 31G1 and 31G2 intersect is a communicating point where one gas vent groove communicates with the other gas vent groove. As a result, the gas flowing through one of the gas vent grooves can branch and flow into the other gas groove at the crossing area.

Therefore, even if the entrances of some of the gas vent grooves 31G1 and 31G2 are blocked with the molten metal, the portions of the gas vent grooves 31G1 and 31G2 whose entrances are blocked with the molten metal are closer to the space outside the mold than the entrances. communicates with the other gas release grooves 31G1 and 31G2 in the intersection area. As a result, the entrances of the plurality of gas vent grooves 31G1 and 31G2 that are not blocked are the intersection regions of the plurality of gas vent grooves 31G1 and 31G2 including the gas vent grooves 31G1 and 31G2 whose entrances are blocked with molten metal. effectively degassing through the downstream portion of the In other words, even if the inlets of some of the plurality of gas vent grooves 31G1 and 31G2 are clogged with molten metal, the path downstream of the intersecting position of the plurality of gas vent grooves 31G1 and 31G2 may function as a gas vent path. be kept. Thereby, the degassing effect is maintained over a long period of time.

In this way, the entrances of some of the plurality of gas venting grooves 31G1 and 31G2 are allowed to be blocked by the molten metal, so that the openings of the entrances can be made smaller. This makes it difficult for the molten metal to penetrate deeply, and can suppress unexpectedly occurring protrusions or dents. For example, even if the gas vent grooves 31G1 and 31G2 are shallow grooves with a depth of 0.3 mm or less, a sufficient gas vent effect can be obtained.

Also, the gas release grooves 31G1 and 31G2 are formed in an arc shape, for example. In this embodiment, the cross-sectional shape perpendicular to the extension direction is formed such that the width dimension is larger than the depth. For example, the gas vent grooves 31G1 and 31G2 are formed with a radius of curvature larger than the depth, and a length twice the radius of curvature is formed larger than the width of the groove. The groove width is the maximum width of the gas vent grooves 31G1 and 31G2 that opens toward the mating surface 31A. The degassing grooves 31G1 and 31G2 are grooves shallower than the semi-circular grooves having the radius of curvature thereof. For example, the gas vent grooves 31G1 and 31G2 may be shallow grooves with a groove width larger than the depth.

In this way, relatively shallow grooves can be formed, and clogging of the casting mold 20 with solidified molten metal can be suppressed. For example, the pitch of the gas vent grooves 31G1 and 31G2 arranged in the same direction is formed to be smaller than three times the width of the gas vent grooves 31G1 and 31G2. Specifically, the width of the gas vent grooves 31G1 and 31G2 is twice or less. By forming the pitch small in this way, the number of the gas vent grooves 31G1 and 31G2 can be increased, and even if the size of the grooves is small, the gas vent effect can be maintained.

In this embodiment, the degassing grooves 31G1 and 31G2 are formed so as to face the tips of the fin-shaped portions 12 to prevent reverse burrs. For example, even if a thin-skin-level burr occurs, since the burr is formed at the tip of the fin-shaped portion 12, it is easy to hit the burr by shot blasting or the like, and the burr can be easily removed by shot blasting. It is possible to eliminate the need for manual removal work.

Here, it is assumed that a supply port 24 is provided on the body portion 11 side, and the molten metal L flows from the supply port 24 toward the fin-shaped portion 12 . In this case, it is assumed that the main flow direction of the molten metal L in the mold space between the mold surfaces 30A and 30C is the direction A from the main body portion 11 toward the tip side of the fin-shaped portion 12 . Both the direction in which the gas vent groove 31G1 extends and the direction in which the gas vent groove 31G2 extends may be inclined with respect to the direction A.

Also, the gas release grooves 31G1 and 31G2 may be formed in the entire mating surface 31A. As a result, the gas vent grooves 31G1 and 31G2 can face the entire outer circumference of the fin-shaped portion 12, and the entire outer circumference of the fin-shaped portion 12 can be vented.

As an example, the gas vent grooves 31G1 and 31G2 may have a shape including a curved groove including a bottom surface that is concave while drawing a curved surface (see FIG. 5). For example, when the gas vent grooves 31G1 and 31G2 are observed in a cross section orthogonal to their extending direction, they are formed in a semicircular or semielliptical recessed shape. The gas vent grooves 31G1 and 31G2 may not be curved grooves. The gas vent groove may be a groove having a polygonal cross section such as a triangular cross section or a square cross section.

An air vent space 100 may be formed in at least one of the portions where the mating surfaces 31A and 31B are formed (see FIG. 3). The air vent space 100 includes an annular annular space 101 formed so as to surround the mold space 22F at a location separated from the tip edge of the mold space 22F for forming the fin-shaped portion 12. The annular space 101 communicates with the space outside the mold through the outer passage 102 . Air may be sucked by an air suction device provided in the space outside the mold. In this case, the air in the gas vent grooves 31G1 and 31G2 is sucked by the air suction device through the outer passage and the annular space 101, thereby sucking the gas in the mold space 22 more effectively.

A method of manufacturing the casting 10 using the casting mold 20 will be described.

With the base mold 28, the intermediate molds 30, 32, 34, 36 and the upper mold 40 assembled, the molten metal L is allowed to flow into the mold space 22 formed by these mold surfaces ( step (a)). At this time, the molten metal L may be supplied from a supply port 24 formed in the lower part of the main body 11 by low-pressure casting.

The supplied molten metal L sequentially fills the mold space 22 from the bottom to the top, as shown in FIG. Taking the space 22F between the mold surfaces 30A and 30C that form one fin-shaped portion 12 as an example, as shown in FIG. . Therefore, in the space 22F, the molten metal pushes out the gas obliquely upward on the tip side of the space 22F. As a result, the gas in the space 22F is smoothly removed through the upper gas release grooves 31G1 and 31G2.

In this step, the flow direction A of the molten metal L from the mold space 22 toward the boundary between the mating surfaces 31A and 31B is the direction that intersects the direction in which the gas vent grooves 31G1 and 31G2 that open at the boundary extend. As shown, the molten metal L may flow into the mold space 22 .

After the molten metal L flows into the mold space 22, the molten metal L in the mold space 22 is solidified by cooling or the like (step (b)). Thereafter, the base mold 28, the intermediate molds 30, 32, 34, 36 and the upper mold 40 are disassembled and the casting 10 is released from each mold surface to manufacture the casting 10.

According to the method of manufacturing the casting mold 20 and the casting 10 configured in this manner, a plurality of outwardly facing mold surfaces 30A, 30C, etc. intersect at least one of the mating surfaces 31A, 31B, etc. Gas release grooves 31G1 and 31G2 are formed. Therefore, the degassing effect is maintained over a long period of time.

For comparison, it is assumed that a plurality of degassing grooves are formed in parallel on the mating surfaces without intersecting each other. In this case, if the entrance of any of the gas venting grooves is blocked, the whole of the gas venting grooves cannot be used as a gas venting path.

In contrast, in the present embodiment, a large number of degassing paths are formed from the mold space 22 to the outside. Therefore, even if the entrances of some of the gas vent grooves 31G1 and 31G2 are blocked, many paths that function as gas vent paths remain. For example, portions of the gas release grooves 31G1 and 31G2 located outside the blocked inlets can be used as gas release paths that connect other unblocked inlets to the outside. Thereby, the degassing effect is maintained over a long period of time.

By using the mold of this embodiment in this way, it is possible to suppress molding defects such as burrs or reverse burrs that occur in castings in the casting mold. By suppressing the occurrence of molding defects in this way, it is possible to reduce post-processes for eliminating molding defects after molding, such as deburring work and build-up work for eliminating reverse burrs. By reducing such post-processes, it is possible to increase the number of products that can be manufactured per unit time, and to reduce manufacturing costs.

Also, the casting of this embodiment is used as an external appearance part, such as an engine part of a motorcycle, so that appearance as well as performance is emphasized. Since the occurrence of molding defects (burrs and reverse burrs) can be prevented as described above, post-processes can be reduced and the quality required for good appearance can be maintained.

Further, the gas release grooves 31G1 and 31G2 are formed as curved grooves including bottom surfaces that are concave while drawing curved surfaces. If the gas vent grooves 31G1 and 31G2 are curved grooves, a large cross-sectional area of the gas vent passage can be easily ensured. For example, if a triangular groove having a triangular cross section and a curved groove have the same depth, the cross-sectional area of the curved groove is larger than that of the triangular groove. Therefore, if the triangular groove and the curved groove have the same cross-sectional area for degassing, the depth of the curved groove can be made smaller than the depth of the triangular groove. If the depth of the curved groove can be reduced, burrs are less likely to occur.

Even if the gas vent grooves 31G1 and 31G2 are not formed as curved grooves including a concave bottom surface while drawing a curved surface, burrs are less likely to occur if the gas vent grooves can be formed shallower than when formed with triangular grooves. Become. For example, the gas release groove may be a groove defined by a boundary that bulges outward from the triangular cross-sectional groove. For example, the gas vent groove may have a polygonal cross-sectional shape with four or more corners, such as a square cross-section or a pentagonal cross-section. Further, for example, the gas release groove may have a cross section defined by a combination of a straight line and two or more curved lines, and may be shallower than the cross-sectional triangular groove. The gas vent groove may be a shallow groove formed by forming the groove width larger than the depth. Here, the depth is the maximum depth, and the groove width is the width of the opening on the mating surface side.

Also, curved grooves are easier to machine than grooves with corners. Further, even if a solidified substance of the molten metal L remains in the gas vent grooves 31G1 and 31G2, it can be easily removed. Therefore, the degassing grooves 31G1 and 31G2 are easier to clean than grooves having angled inner surfaces. As a result of being able to clean the gas vent grooves 31G1 and 31G2, when the casting mold 20 is repeatedly used for casting, the releasability from the gas vent grooves 31G1 and 31G2 can be improved. For example, if the gas release groove is a groove surrounded by a curved surface or a groove surrounded by a curved surface and a flat surface, compared to a groove having corners, the cleaning property can be improved more easily.

In addition, since the gas release grooves 31G1 and 31G2 are formed in the second mating surfaces such as the mating surface 31A which are located above the first mating surfaces such as the mating surface 31B, the molten metal is When the molten metal flows into the portion forming the fin-shaped portion 12 from below, the molten metal pushes the gas obliquely upward. This gas is smoothly pushed out through the gas release grooves 31G1 and 31G2 formed in the upper second mating surface.

Further, in order to form the fin-shaped portion 12 with a mold, the molten metal L must pass through a narrow space to reach the tip of the fin-shaped portion 12 . If the molten metal L is not sufficiently spread over the entire fin-shaped portion 12 or if air remains at the tip of the fin-shaped portion 12, molding defects such as dents will occur around the fin-shaped portion 12, particularly at the tip. easy. Therefore, the gas release grooves 31G1 and 31G2 are the boundaries between the first mold surface such as the upper mold surface 30C and the second mold surface such as the lower mold surface 30A, and extend outward from the periphery of the fin-shaped portion 12. When the fin-shaped portion 12 is formed so as to face in the opposite direction, it is possible to smoothly perform degassing at a portion where molding defects are likely to occur, and the fin-shaped portion 12 can be molded satisfactorily.

In addition, the plurality of gas vent grooves 31G1 and 31G2 extend in multiple directions at portions that open toward the first mold surface such as the upper mold surface 30C and the second mold surface such as the lower mold surface 30A. Therefore, the plurality of gas vent grooves 31G1 and 31G2 can be opened in the entire area around the fin-shaped portion 12. As shown in FIG.

For comparison, it is assumed that a plurality of gas vent grooves are formed so as to extend in parallel without intersecting each other. In this case, the plurality of gas vent grooves can be opened only from the same direction with respect to the mold space. For example, assuming that a plurality of gas vent grooves are formed along the mold drawing direction, a plurality of gas vent grooves are formed in the periphery of the mold space for forming the fin-shaped portion 12, which is perpendicular to the mold drawing direction. A large number of punched grooves can be opened at narrow intervals. However, in the periphery of the mold space for forming the fin-shaped portion 12, the gas vent grooves cannot be opened, or only a small number of openings can be made at wide intervals on the edges parallel to the drawing direction or with a small inclination. Not too much.

On the other hand, if the plurality of gas vent grooves 31G1 and 31G2 extend linearly while intersecting and are formed in a mesh shape, the plurality of gas vent grooves 31G1 and 31G2 form the mold space forming the fin-shaped portion 12. The openings can be made at narrow intervals both to the edges perpendicular to the drawing direction P and to the edges along the drawing direction P of 22F. For this reason, a plurality of gas vent grooves 31G1 and 31G2 can be opened in a large number along the entire periphery of the mold space 22F forming the fin-shaped portion 12, and the cross-sectional areas of the individual gas vent grooves 31G1 and 31G2 are small. Also, gas can be effectively vented by a large number of gas vent grooves 31G1 and 31G2. As a result of being able to reduce the cross-sectional area of each of the gas vent grooves 31G1 and 31G2, it becomes difficult for molten metal to enter the gas vent grooves 31G1 and 31G2, and unexpected projections or dents are suppressed.

Note that the shape of the casting 10 is not particularly limited. The casting may not have fin-shaped portions. In a casting mold for forming a casting, the configuration related to the gas release groove can be applied to a portion where a plurality of molds are joined.

The mating surfaces of the multiple molds do not need to be horizontal, but may be parallel to the direction of gravity or may be inclined with respect to both the direction of gravity and the horizontal direction.

In this embodiment, an example in which the casting mold 20 is configured by a combination of the six molds 28, 30, 32, 34, 36, 40 has been described. However, the number of molds that make up the casting mold is arbitrary. The casting mold may consist of a combination of two molds. Also, a plurality of molds need not be combined vertically, and may be combined horizontally or obliquely.

In this embodiment, one of the opposing mating surfaces, here, the upper mating surfaces 31A and 41, is provided with the gas release grooves 31G1 and 31G2. The gas release groove may be formed in at least one of the first mating surface and the second mating surface that face each other. For example, the gas release groove may be formed in the lower first mating surface. A first gas release groove is formed in the first mating surface, a second gas release groove is formed in the second mating surface, and the first gas release is performed in a state in which the first mating surface and the second mating surface face each other. A configuration in which the groove and the second gas vent groove intersect may be employed.

In this embodiment, an example in which the plurality of gas vent grooves 31G1 and 31G2 are formed in a mesh pattern has been described. A shape example in which a plurality of gas vent grooves intersect and extend outward from between the mold surfaces is not limited to this example. For example, a plurality of degassing grooves may meander and intersect with each other and extend outward from between the mold surfaces.

The gas vent grooves 31G1 and 31G2 may not be curved grooves. The gas vent groove may be a groove with a triangular or square cross section.

It should be noted that the configurations described in the above embodiment and modifications can be appropriately combined as long as they do not contradict each other.

In this embodiment, the casting mold is used for molding the fin-shaped portion, but the present invention may also be applied to molding other portions. Castings may be engine parts other than cylinder heads, and the present invention can be applied to parts other than engines. INDUSTRIAL APPLICABILITY The present invention is suitably used for a mold for forming a portion where gas may be forced into the tip portion, such as a thin-walled portion and a small-diameter portion. For example, in addition to the fin-shaped portion, the present invention can be similarly applied to protruding portions such as a blade portion, a collar portion, and a needle-like portion. Even with such a product, it is possible to degas the tip portion and prevent molding defects, so that it can be suitably used.

The metal mold of this embodiment is an example, and other forms may be used. That is, the present invention can be applied to the case of molding the protruding portion using two molds. A space defining the projecting portion is formed by two molds. Further, the above-described degassing groove is formed so as to face the tip of the protruding portion where the molten metal flows and becomes a dead end.

The gas release groove may be formed to extend in a curved shape instead of a linear shape. A gas passage having a large passage area may be formed outside the region where the gas vent groove is formed. This makes it easier to control the passage through which the gas escapes, and makes it easier to suck the gas from the space outside the mold. In this embodiment, the example in which the gas vent grooves are formed in both upper and lower molds facing each other has been described. good.

Although the present invention has been described in detail as above, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that numerous variations not illustrated can be envisioned without departing from the scope of the invention.

As explained above, this specification includes the following aspects.

A first aspect has a first mold part having a first mold surface and a first mating surface, a second mold surface and a second mating surface, and is continuous with the first mold surface. and a second mold part that is combined with the first mold part in a state in which the second mold surface is arranged in such a manner that the second mating surface is opposed to the first mating surface. , wherein at least one of the first mating surface and the second mating surface has a plurality of gas vent grooves extending outward from between the first mold surface and the second mold surface while intersecting A casting mold being formed.

Thus, at least one of the first mating surface and the second mating surface has a plurality of degassing grooves extending outward from between the first mold surface and the second mold surface while intersecting each other. Since it is formed, a large number of degassing paths are formed. At the position where the gas venting grooves intersect, the gas venting paths merge and branch. Therefore, even if the inlets of some of the plurality of gas venting grooves are clogged with molten metal, the downstream path of the intersecting position can be made to function as the gas venting path. Thereby, the degassing effect is maintained over a long period of time. In addition, the opening of the inlet can be made smaller by allowing a portion of the inlet to be blocked by the molten metal. This makes it difficult for molten metal to enter. Therefore, projections or depressions that occur unexpectedly are suppressed.

From the viewpoint of the first aspect, the cross-sectional shape of the gas venting groove is not limited, and may be a curved groove or a groove having corners.

As in the second aspect, in the casting mold according to the first aspect, the plurality of degassing grooves may include curved grooves including bottom surfaces that are concave while forming curved surfaces. When trying to secure the same cross-sectional area for the triangular cross-sectional groove and the curved groove, the depth of the curved groove can be made smaller than the depth of the triangular cross-sectional groove. If the depth of the curved groove can be reduced, it becomes more difficult for the molten metal to enter, and unexpected projections or depressions are further suppressed.

A third aspect is the casting mold according to the first or second aspect, wherein the second mold surface is arranged to face the first mold surface upward, and the plurality of The gas release groove of includes one formed in the second mating surface. In this case, since the gas vent groove is on the upper side, the molten metal flowing from below into the mold space between the first mold surface and the second mold surface pushes the gas obliquely upward. This gas is smoothly pushed out by the vent grooves on the upper side. This makes it difficult for the gas to remain in the mold space.

A fourth aspect is a casting mold according to any one of the first to third aspects for forming a fin-shaped portion in a casting, wherein the first mold surface has the fin-shaped a first fin-forming mold surface forming one side of the portion; the second mold surface including a second fin-forming mold surface forming the other side of the fin-shaped portion; The gas vent groove is a boundary between the first mold surface and the second mold surface, and is formed so as to extend outward from the periphery of the fin-shaped portion. In order to mold the fin-shaped portion, the molten metal should reach the tip of the fin-shaped portion through a narrow space. If the molten metal does not spread sufficiently over the fin-shaped portions or if air remains at the tips of the fin-shaped portions, molding defects such as dents are likely to occur around the fin-shaped portions, particularly at the tips. By smoothly venting gas from this portion, the fin-shaped portion can be favorably molded.

A fifth aspect is the casting mold according to any one of the first to fourth aspects, wherein the plurality of gas vent grooves are provided on the first mold surface and the second mold surface Including those extending in a plurality of directions in the portion that opens toward. In this case, a plurality of gas vent grooves are opened toward the mold space in the entire area around the mold space where the first mold surface and the second mold surface are joined, and the gas is vented. done efficiently. Thereby, the opening of the entrance of the gas release groove can be made smaller. This makes it difficult for molten metal to enter. Therefore, projections or depressions that occur unexpectedly are suppressed.

Further, a casting manufacturing method according to a sixth aspect has a first mold component having a first mold surface and a first mating surface, a second mold surface and a second mating surface, and The second mold surface is disposed so as to be continuous with the first mold surface, and the second mold component is assembled with the first mold component in a state in which the second mating surface is opposed to the first mating surface. a second mold part to be mated, wherein the first mold part intersects with at least one of the first mating surface and the second mating surface and extends outward from between the first mold surface and the second mold surface. A method for manufacturing a casting using a casting mold, wherein a plurality of gas vent grooves directed toward the (b) the molten metal in the mold space is solidified; Prepare. According to this manufacturing method, castings with few shape defects can be manufactured.

10 casting 12 fin-shaped portion 20 casting mold 22 mold space 28 base mold 28A mold surface 29 mating surfaces 30, 32, 34, 36 intermediate mold 30A lower mold surface 30C upper mold surface 31A mating surface 31B Mating surface 31G1 Gas venting groove 31G2 Gas venting groove 40 Upper upper mold 40A Mold surface 41 Mating surface

Claims (9)

a first mold part having a first mold surface and a first mating surface;
Having a second mold surface and a second mating surface, the second mold surface is disposed so as to be continuous with the first mold surface, and the second mold surface is aligned with the first mating surface. a second mold part that is combined with the first mold part with the faces facing each other;
a first type having
A second mold in which a casting is cast in a state where the casting is separably united with the first mold at the dividing surface, and the casting is released from the first mold by moving in a direction away from the first mold;
with
A plurality of degassing grooves extending outward from between the first mold surface and the second mold surface while intersecting at least one of the first mating surface and the second mating surface of the first mold. A casting mold in which is formed. A casting mold according to claim 1,
The casting mold, wherein the plurality of gas vent grooves include a curved groove including a bottom surface that is recessed while drawing a curved surface. The casting mold according to claim 1 or claim 2,
A casting mold, wherein an annular space surrounding the gas release groove and an outer passage communicating between the annular space and the space outside the mold are formed. The casting mold according to any one of claims 1 to 3,
A main body forming space for forming the main body of the casting is formed by the first mold and the second mold,
A mold space for forming a thin portion forming a thin portion extending from the main body is formed between the first mold surface and the second mold surface,
A plurality of combinations of the first mold surface and the second mold surface are provided, and the mold spaces for forming the thin-walled shape portion are formed so as to be arranged side by side with a plurality of intervals,
A casting mold, wherein the degassing grooves are formed on the tip side of each of the plurality of mold spaces for forming thin-walled portions. a first mold part having a first mold surface and a first mating surface;
Having a second mold surface and a second mating surface, the second mold surface is disposed so as to be continuous with the first mold surface, and the second mold surface is aligned with the first mating surface. a second mold part that is combined with the first mold part with the faces facing each other;
with
At least one of the first mating surface and the second mating surface is provided with a plurality of degassing grooves extending outward from between the first mold surface and the second mold surface while intersecting each other. ,
The second mold surface is arranged facing upward with respect to the first mold surface,
The casting mold, wherein the plurality of gas vent grooves are formed in the second mating surface. A casting mold according to any one of claims 1 to 3 and 5 for forming a fin-shaped portion in a casting,
The first mold surface includes a first fin-forming mold surface that forms one surface side of the fin-shaped portion,
The second mold surface includes a second fin-forming mold surface that forms the other surface side of the fin-shaped portion,
The plurality of gas vent grooves are a boundary between the first mold surface and the second mold surface, and are formed so as to extend outward from the periphery of the fin-shaped portion. . The casting mold according to any one of claims 1 to 6 ,
The casting mold, wherein the plurality of gas vent grooves extend in a plurality of directions in a portion opening toward the first mold surface and the second mold surface. a first mold part having a first mold surface and a first mating surface;
Having a second mold surface and a second mating surface, the second mold surface is disposed so as to be continuous with the first mold surface, and the second mold surface is aligned with the first mating surface. a second mold part that is combined with the first mold part with the faces facing each other;
with
At least one of the first mating surface and the second mating surface is provided with a plurality of gas vent grooves extending outward from between the first mold surface and the second mold surface while intersecting each other. , a method for manufacturing a casting using a casting mold,
(a) in a state in which the first mold part and the second mold part are combined, a molten metal is introduced into a mold space formed inside the first mold surface and the second mold surface; and a step in which
(b) solidification of the molten metal in the mold space;
with
A casting manufacturing method , wherein in the step (a), air in the gas vent groove is sucked by an air suction device . A method for manufacturing a casting according to claim 8,
An annular space surrounding the gas vent groove around the mold space between the first mold surface and the second mold surface, and an outer passage communicating between the annular space and the space outside the mold are formed. is,
The casting manufacturing method, wherein in the step (a), the air in the gas vent groove is sucked by the air suction device through the annular space and the outer passage.

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